Investigation of the haemostatic effects of freeze dried extracts of selected Kenyan plants

Abstract

Introduction: “Hemorrhage is responsible for 30% to 40% of trauma mortality and accounts for almost 50% of the deaths occurring in the initial 24 hours following the traumatic incident”. The approach to “new drugs through natural products has proved to be the single most successful strategy” for the discovery of new drugs. The current study investigated the effect and mechanisms of action of Tridax procumbens, Asphillia africana, Euphorbia tirucalli and Terminalia brownii that have been used traditionally to stop bleeding following accidental cuts and after traditional circumcision. Setting: The study was conducted in four institutions. Preparation of freeze dried extracts was carried out at the International Centre for Insect Physiology and Ecology (ICIPE) laboratory. Bleeding and clotting tests were carried out at University of Nairobi, medical physiology laboratory. Prothrombin and activated partial thromboplastin time were carried out at Kenyatta National Hospital, haematology department. Thromboelastography was carried out at Kenyatta University, physiology laboratory. Main Objective: To investigate the effect and mechanism of action of freeze dried extracts of Tridax procumbens Linn, Terminalia brownii, Euphorbia tirucalli and Asphillia africana on haemostasis. Materials and methods: Freeze dried extract of the selected plants was prepared and dose determined for the study. Twelve male New Zealand white rabbits were randomly allocated to two groups (control and test). Blood was collected under standard procedures. Duke’s method was used for bleeding time while capillary method was used for clotting time. ACL Elitepro machine was used to do prothrombin time and activated partial thromboplastin time. Thromboelastogrpahy

was done for the most potent extracts. Data was analysed using indepent t test and results presented as mean± standard error of means. Differences were considered to be significant if P < 0.05. Results: The percentage yield of the extract was; Tridax procumbens (0.8%), Terminalia brownii (0.5%), Euphorbia tirucalli (0.2%) and Aspillia Pluriseta (1.3%). Bleeding and Clotting time: The bleeding time was reduced by freeze dried leaf extract of Tridax procumbens (p = 0.0068) and by freeze dried bark extract of Terminalia brownii (p=0.0068). Freeze dried leaf extract of Asphillia africana increased the bleeding time (p=0.01). The clotting time was reduced by freeze dried leaf extract of Tridax procumbens (p = 0.038), freeze dried bark extract of Terminalia brownii (p=0.043) and by freeze dried stem extract of Euphorbia tirucalli (p=0.01). Prothrombin and Activated partial thromboplastin time: The prothrombin time was reduced by freeze dried leaf extract of Tridax procumbens (p = 0.004), freeze dried bark extract of Terminalia brownii (p<0.001) and Freeze dried stem extract of Euphorbia tirucalli (p=0.001). Activated partial thromboplastin time was reduced by freeze dried leaf extract of Tridax procumbens (p< 0.001), freeze dried bark extract of Terminalia brownii (p<0.001) and by Freeze dried stem extract of Euphorbia tirucalli (p<0.001). Thromboelastography: Four parameters of Thromboelastography were tested. Freeze dried leaf extract of Tridax procumbens reduced the r time (p =0.04), k time (p=0.04) and maximum amplitude (p =0.026) but increased the alpha angle (p =0.01). Freeze dried bark extract of Terminalia brownii did not have statistically significant differences on Thromboelastography variables. Conclusion: Tridax procumbens and Terminalia brownii have activation effect on the platelets. Tridax procumbens, Euphorbia tirucalli and Terminalia brownii have viiactivation effect on common coagulation pathway. Tridax procumbens has more effect on factor